We've seen the trailers, and now the BBC has released posters and episode descriptions teasing the next four episodes of Doctor Who. Steer clear if you want to remain avoid minor spoilers in advance of the March 30th premiere, or take a peek at what's in store for the Doctor and Clara Oswald, the Impossible Girl.

You may have spotted the BBC America trailer above this weekend at EW, but here it is in its YouTube glory.

Steven Moffat is teasing some exciting adventures and monsters:

A haunted house, a submarine, a planet with cool rings, Victorian Yorkshire, a journey into the TARDIS, Dame Diana Rigg and her daughter Rachael Stirling together on screen for the first time, new Cybermen, and the Doctor's greatest secret revealed.

and:

Plenty of new monsters! Watch out for the Spoonheads, the Whispermen, and - my favorite - the Vigil. Oh and Neil Gaiman has done something horrible with the Cybermen!

And as for the Doctor's new companion, Moffat says, "It's all new for the Doctor - this time the greatest mystery in the universe is standing right next to him."

But while the Doctor contemplates this mystery that is Clara, here is where and when they're headed:

The Bells of Saint John

The Doctor’s search for Clara Oswald brings him to modern day London, where Wi-Fi is everywhere. Humanity lives in a Wi-Fi soup. But something dangerous is lurking in the signals, picking off minds and imprisoning them. As Clara becomes the target of this insidious menace, the Doctor races to save her and the world from an ancient enemy.

Episode credits: Written by Steven Moffat, directed by Colm McCarthy (Ripper Street, The Tudors), and produced by Denise Paul (Taggart).

The Rings of Akhaten

Clara wants to see something awesome, so the Doctor whisks her off to the inhabited rings of the planet Akhaten, where the Festival of Offerings is in full swing. Clara meets the young Queen of Years as the pilgrims and natives ready for the ceremony. But something is stirring in the pyramid, and a sacrifice will be demanded.

Episode credits: Written by Neil Cross (Mama, Luther), directed by Farren Blackburn (Luther, The Fades) and produced by Denise Paul

Cold War

The Doctor and Clara land on a damaged Russian Submarine in 1983 as it spirals out of control into the ocean depths. An alien creature is loose on board, having escaped from a block of Arctic ice. With tempers flaring and a cargo of nuclear weapons on board, it’s not just the crew but the whole of humanity at stake!

Clara and the Doctor arrive at Caliburn House, a haunted mansion sat alone on a desolate moor. Within its walls, a ghost hunting Professor and a gifted psychic are searching for the Witch of the Well. Her apparition appears throughout the history of the building, but is she really a ghost? And what is chasing her?

Episode credits: Written by Neil Cross and directed by Jamie Payne (The Hour, Call the Midwife).